Activate Horn when locking and unlocking doors possible - do NOT have factory alarm

I have a 2009 335i and unfortunately do not have the factory alarm. I'm considering adding it as its not crazy expensive.

My main reason is that I want an audible conformation when I lock my doors. If I was to add the alarm its primarily to get the chirp.

In the meantime, is there some way to code the car to activate the horn when locking the doors? What if I just bought the alarm speaker and hooked in up in the wheel well. Could I code it it to chirp without having to install and code the rest of the alarm system?

The only way is to install the factory alarm, if your car is pre-wired for it then its a quick install and then code for it. For what its worth, before my car god coded for the oem alarm, one of the options that didn't work was the chirp.

The only way is to install the factory alarm, if your car is pre-wired for it then its a quick install and then code for it. For what its worth, before my car god coded for the oem alarm, one of the options that didn't work was the chirp.

I have heard that the coding is absolutely necessary for the chirp to work so that jives with what I've heard.

How much did you pay for coding? Did you have a dealer do it or can a forum member with a laptop and the right cable do it?

You might check out the RemoteKey+ as well. It simulates the alarm (chirps, LED in the mirror) and it also allows you to open and close your windows with the FOB as well as fold the mirrors (if you have that option).

You might check out the RemoteKey+ as well. It simulates the alarm (chirps, LED in the mirror) and it also allows you to open and close your windows with the FOB as well as fold the mirrors (if you have that option).

If you're gonna spend all that $$ for the Remote Key, you might as well just get the factory alarm and actually HAVE a functioning alarm instead of a fake. The price is about the same.

You can already open windows/roof & fold mirrors from FOB from factory. Simple to code in to be able to close your windows/roof from FOB.

And no, there is no way to code horn to signal lock/unlock. Factory system that does this does not use the horn anyway - it uses the alarm system siren to sound a chirp - so no alarm system - no chirping.

And coding the alarm is simple to DIY, if you don't want to get involved with coding, find someone near you to do it - just make sure they really know what the hell they are doing or bad things can happen

Dealer will charge ~$300 to do coding of new alarm - they do not have the capabilities to code individual items as we are doing here - they actually have to update the entire car software at the same time - which could take a couple hrs of the car hooked up to the machine depending on whether it all goes thru the 1st time or not...

^^ you assume he is pre-wired. I was not so this made a lot of sense. I think they stop pre-wiring at some point in 2009.

And as far as coding, that is a pretty steep hill for some folks. You have to buy a $100 cable and then do your research on the required software. You also may screw things up pretty good. The RemoteKey+ is a simple install and works perfectly. Plus you can change the settings very easily with a USB cable.

Well, yes, I was. I saw he has an 09' my 09' was prewired, but it has BD of 2/09

If not prewired, then the Remote Key would be the cheaper way to go...

Thanks for all the help. I wasn't aware that the production date affected whether or not I'm pre-wired. So I actually had Tischer run my VIN before pulling the trigger on the factory alarm. My PD is 06/2009 so I'm SOL and not pre-wired.

I'm going to go with remotekey+. My main gripe is not having any audible confirmation when I lock my doors. I guess $250 is a lot to pay for a chirp and the ability to control the windows and moonroof with my key FOB but I'm going to see if I can find a used one.

An actual functional alarm would be nice to alert me if someone is messing with my car and if I was pre-wired i'd go with factory over remote key+ in a heartbeat.